Department of Molecular Biology, Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv, Ukraine.
Department of Pediatrics, National Bohomolets Medical University, Kyiv, Ukraine.
Endocr Regul. 2020 Jul 1;54(3):196-206. doi: 10.2478/enr-2020-0022.
The aim of the present investigation was to study the expression of genes encoding homeobox proteins ZEB2 (zinc finger E-box binding homeobox 2), TGIF1 (TGFB induced factor homeobox 1), SPAG4 (sperm associated antigen 4), LHX1 (LIM homeobox 1), LHX2, LHX6, NKX3-1 (NK3 homeobox 1), and PRRX1 (paired related homeobox 1) in U87 glioma cells in response to glucose deprivation in control glioma cells and cells with knockdown of ERN1 (endoplasmic reticulum to nucleus signaling 1), the major pathway of the endoplasmic reticulum stress signaling, for evaluation of it possible significance in the control of glioma growth through ERN1 signaling and chemoresistance.
The expression level of homeobox family genes was studied in control (transfected by vector) and ERN1 knockdown U87 glioma cells under glucose deprivation condition by real-time quantitative polymerase chain reaction.
It was shown that the expression level of ZEB2, TGIF1, PRRX1, and LHX6 genes was up-regulated in control glioma cells treated by glucose deprivation. At the same time, the expression level of three other genes (NKX3-1, LHX1, and LHX2) was down-regulated. Furthermore, ERN1 knockdown of glioma cells significantly modified the effect glucose deprivation condition on the expression almost all studied genes. Thus, treatment of glioma cells without ERN1 enzymatic activity by glucose deprivation condition lead to down-regulation of the expression level of ZEB2 and SPAG4 as well as to more significant up-regulation of PRRX1 and TGIF1 genes. Moreover, the expression of LHX6 and NKX3-1 genes lost their sensitivity to glucose deprivation but LHX1 and LHX2 genes did not change it significantly.
The results of this investigation demonstrate that ERN1 knockdown significantly modifies the sensitivity of most studied homeobox gene expressions to glucose deprivation condition and that these changes are a result of complex interaction of variable endoplasmic reticulum stress related and unrelated regulatory factors and contributed to glioma cell growth and possibly to their chemoresistance.
本研究旨在研究锌指 E 盒结合同源盒 2（ZEB2）、转化生长因子 B 诱导因子同源盒 1（TGIF1）、精子相关抗原 4（SPAG4）、LIM 同源盒 1（LHX1）、LHX2、LHX6、NK3 同源盒 1（NKX3-1）和配对相关同源盒 1（PRRX1）基因在 U87 神经胶质瘤细胞中对葡萄糖剥夺的表达，在对照神经胶质瘤细胞和 ERN1（内质网到核信号 1）敲低的细胞中，ERN1 信号在控制神经胶质瘤生长和化学抗性方面的可能意义，内质网应激信号的主要途径。
通过实时定量聚合酶链反应研究葡萄糖剥夺条件下对照（转染载体）和 ERN1 敲低 U87 神经胶质瘤细胞中同源盒家族基因的表达水平。
结果表明，葡萄糖剥夺处理的对照神经胶质瘤细胞中 ZEB2、TGIF1、PRRX1 和 LHX6 基因的表达水平上调。同时，另外三个基因（NKX3-1、LHX1 和 LHX2）的表达水平下调。此外，神经胶质瘤细胞中 ERN1 的敲低显著改变了葡萄糖剥夺条件对几乎所有研究基因表达的影响。因此，无 ERN1 酶活性的神经胶质瘤细胞在葡萄糖剥夺条件下的处理导致 ZEB2 和 SPAG4 表达水平下调，以及 PRRX1 和 TGIF1 基因的更显著上调。此外，LHX6 和 NKX3-1 基因的表达对葡萄糖剥夺失去敏感性，但 LHX1 和 LHX2 基因的表达变化不显著。
本研究结果表明，ERN1 的敲低显著改变了大多数研究的同源盒基因表达对葡萄糖剥夺条件的敏感性，这些变化是内质网应激相关和不相关调节因子的复杂相互作用的结果，有助于神经胶质瘤细胞的生长，并可能有助于其化学抗性。
